Edge-lit lighting fixture sensor shield

ABSTRACT

An edge-lit lighting fixture includes a light emitting panel (LEP) and a light emitting diode (LED) light source that is positioned proximal to a perimeter edge of the LEP and configured to emit a light into the LEP through the perimeter edge. At least a portion of the light is emitted through the broad surface of the LEP as an illumination light to illuminate an area. The edge-lit lighting fixture further includes a sensor positioned at a broad surface of the LEP to detect ambient light in the area. The LED light source is powered on based on the light sensor. The edge-lit lighting fixture also includes a sensor shield positioned around a portion of the sensor to block the illumination light from directly reaching the sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of and claims priorityto U.S. Nonprovisional patent application Ser. No. 16/588,665, filedSep. 30, 2019, and titled “Edge-Lit Lighting Device,” which is acontinuation of and claims priority to U.S. Nonprovisional patentapplication Ser. No. 15/901,625, filed Feb. 21, 2018, and titled“Edge-Lit Lighting Device,” which is a continuation of and claimspriority to U.S. Nonprovisional patent application Ser. No. 15/186,122,filed Jun. 17, 2016, and titled “Edge-Lit Lighting Device,” which is acontinuation application of and claims priority to U.S. Nonprovisionalpatent application Ser. No. 14/011,446, filed Aug. 27, 2013, and titled“Light Distribution Control of an Edge-Lit Lighting Device.” The entirecontents of all of the foregoing applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates generally to light distribution control,in particular to light distribution control of an edge-lit lightingdevice.

BACKGROUND

Edge-lit lighting fixtures include a light emitting panel (LEP) thatemits light through a broad side of the LEP. For example, the lightingfixture may include a light source, such as a light emitting diode(LED), that is positioned close to a narrow side of the LEP. Light fromthe light source may enter the LEP through the narrow side of the LEP.The light from the light source that enters the LEP through the narrowside of the LEP may be emitted by the LEP through the broad side of theLEP to illuminate a space around the lighting fixture. A distributionpattern of the light emitted by the LEP of the lighting fixture maydepend on, for example, the intensity of the light that is emitted bythe light source and that enters the narrow side of the LEP. When theLEP has multiple narrow sides (i.e., the LEP is not round), thedistribution pattern of the light emitted by the LEP may also depend onthe particular narrow side of multiple narrow sides of the LEP throughwhich the light from the light source enters the LEP.

In some cases, the distribution pattern of light emitted by a standardedge-lit lighting fixture may not be desirable for some applicationsand/or situations. For example, an edge-lit lighting fixture that emitslight that equally illuminates all parts of an area around the lightingfixture may not be desirable. To illustrate, a series of lightingfixtures may be powered to provide lighting for a parking (deck) garage.However, it may be undesirable for the light to illuminate areas outsideof the parking garage. To avoid illuminating some areas around thelighting fixtures, the lighting fixtures may need to include structuressuch as inserts and/or shields. Furthermore, the need for illuminationof an area around the lighting fixture may change based on particularsituations. For example, an area around the lighting fixture may need tobe illuminated only when the area is occupied.

Accordingly, a lighting device that can be set and/or adjusted to emitlight that has a particular distribution pattern may be desirable.

SUMMARY

In general, the present disclosure relates to light distribution controlof an edge-lit lighting device. In an example embodiment, an edge-litlighting device includes a light emitting panel (LEP), a first pluralityof light sources, and a second plurality of LEDs. The first plurality oflight sources are positioned proximal to a first narrow side of the LEPand are configured to emit a first light into the LEP through the firstnarrow side. The first light has a first intensity level. The secondplurality of LEDs are positioned proximal to a second narrow side of theLEP and are configured to emit a second light into the LEP through thesecond narrow side. The second light has a second intensity level thatis different from the first intensity level. The first intensity leveland the second intensity level are set to achieve a particulardistribution pattern of an output light emitted out through a broad sideof the LEP.

In another example embodiment, an edge-lit lighting device includes alight emitting panel (LEP), a first plurality of light sources, and asecond plurality of light sources. The first plurality of LEDs arepositioned proximal to a first narrow side of the LEP and are configuredto emit a first light into the LEP through the first narrow side. Thefirst light has a first intensity level. The second plurality of LEDsare positioned proximal to a second narrow side of the LEP and areconfigured to emit a second light into the LEP through the second narrowside. The second light has a second intensity level. The LEP isconfigured to emit an output light through a broad side of the LEP. Thefirst intensity level and the second intensity level of the second lightare adjustable. The distribution pattern of the output light ischangeable by adjusting one of the first intensity level and the secondintensity level.

In another example embodiment, a method of controlling lightdistribution of an edge-lit lighting device includes installing anedge-lit lighting device that includes a light emitting panel (LEP), afirst plurality of light sources positioned proximal to a first narrowside of the LEP and configured to emit a first light into the LEPthrough the first narrow side, and a second plurality of light sourcespositioned proximal to a second narrow side of the LEP and configured toemit a second light into the LEP through the second narrow side. Themethod further includes setting an intensity level of the first lightand setting an intensity level of the second light.

In another example embodiment, an edge-lit lighting device includes alight emitting panel (LEP) having a broad side and a plurality narrowsides. The edge-lit lighting device further includes multiple lightsources. Each of the multiple light sources is positioned proximal to arespective narrow side of the plurality of narrow sides and oriented toemit a respective light into the LEP through the respective narrow sideof the plurality of narrow sides. A distribution of an output lightemitted through the broad side of the LEP is changeable by powering onat least one light source of the multiple light sources that are poweredoff and by powering off one or more light sources of the multiple lightsources that are powered on.

In another example embodiment, an edge-lit lighting fixture includes alight emitting panel (LEP) and a light emitting diode (LED) light sourcepositioned proximal to a perimeter edge of the LEP and configured toemit a light into the LEP through the perimeter edge. At least a portionof the light is emitted through a broad surface of the LEP as anillumination light to illuminate an area. The edge-lit lighting fixturefurther includes a sensor positioned at the broad surface of the LEP todetect ambient light in the area, where the LED light source is poweredon based on the sensor. The edge-lit lighting fixture also includes asensor shield positioned around a portion of the sensor to block theillumination light from directly reaching the sensor.

In another example embodiment, an edge-lit lighting fixture includes alight emitting panel (LEP) and a light emitting diode (LED) light sourcepositioned proximal to a perimeter edge of the LEP and configured toemit a light into the LEP through the perimeter edge. At least a portionof the light is emitted through a broad surface of the LEP as anillumination light to illuminate an area. The edge-lit lighting fixturefurther includes a sensor positioned at the broad surface of the LEP todetect ambient light in the area, where the LED light source is poweredon based on the sensor. The edge-lit lighting fixture also includes asensor shield positioned around a portion of the sensor to block theillumination light from directly reaching the sensor and a framepositioned adjacent the perimeter edge of the LEP.

These and other aspects, objects, features, and embodiments will beapparent from the following description and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying figures, which are notnecessarily to scale, and wherein:

FIGS. 1A and 1B illustrates a lighting device including a light emittingpanel (LEP) in accordance with an example embodiment;

FIG. 2A illustrates the lighting device of FIG. 1A including a set oflight emitting diodes (LEDs) that are powered on in accordance with anexample embodiment;

FIG. 2B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 2A in accordance with an example embodiment;

FIG. 3A illustrates the lighting device of FIG. 1A including two sets ofLEDs that are powered on in accordance with an example embodiment;

FIG. 3B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 3A in accordance with an example embodiment;

FIG. 4A illustrates the lighting device of FIG. 1A including two sets ofLEDs that are powered on in accordance with another example embodiment;

FIG. 4B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 4A in accordance with an example embodiment;

FIG. 5A illustrates the lighting device of FIG. 1A including three setsof LEDs that are powered on in accordance with an example embodiment;

FIG. 5B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 5A in accordance with an example embodiment;

FIG. 6A illustrates the lighting device of FIG. 1A including four setsof LEDs that are powered on in accordance with an example embodiment;

FIG. 6B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 6A in accordance with an example embodiment;

FIGS. 7A-7D are Iso-footcandle plots illustrating effects of differentintensity levels of light from different light sources on the lightdistribution pattern of a lighting device in accordance with an exampleembodiment;

FIG. 8 is a flowchart illustrating a method of controlling lightdistribution of the edge-lit lighting device of FIG. 1A in accordancewith an example embodiment;

FIG. 9 illustrates the lighting device of FIG. 1A according to anotherexample embodiment;

FIG. 10 illustrates the sensor shield attached to the sensor of thelighting device of FIG. 9 according to an example embodiment;

FIG. 11 illustrates the sensor of the lighting device of FIG. 9according to an example embodiment;

FIGS. 12 and 13 illustrate different views of the sensor shield of thelighting device of FIG. 9 according to an example embodiment; and

FIG. 14 illustrates the inside of the lighting device of FIG. 9according to an example embodiment.

The drawings illustrate only example embodiments and are therefore notto be considered limiting in scope. The elements and features shown inthe drawings are not necessarily to scale, emphasis instead being placedupon clearly illustrating the principles of the example embodiments.Additionally, certain dimensions or placements may be exaggerated tohelp visually convey such principles. In the figures, the same referencenumerals used in multiple drawings designate like or corresponding butnot necessarily identical elements.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

In the following paragraphs, particular embodiments will be described infurther detail by way of example with reference to the figures. In thedescription, well known components, methods, and/or processingtechniques are omitted or briefly described. Furthermore, reference tovarious feature(s) of the embodiments is not to suggest that allembodiments must include the referenced feature(s).

Turning now to the drawings, example embodiments are described. FIGS. 1Aand 1B illustrate a lighting device including a light emitting panel(LEP) in accordance with an example embodiment. The lighting device 100may be set and/or adjusted to emit an output light that has a desiredlight distribution pattern. For example, the lighting device 100 mayemit light such that a portion of an area around the lighting device 100is relatively highly illuminated by the light while another portion ofthe area is dimly illuminated.

The lighting device 100 includes the LEP 102 and a frame 104. In someexample embodiments, the lighting device 100 may also include anoptional sensor 105. The LEP 102 may be made from an acrylic material,glass, or another suitable material, that allows light to enter throughone or more narrow sides of the LEP 102 and to be emitted through one ormore broad sides of the LEP 102. The LEP 102 may have an octagonal shapeas illustrated in FIG. 1B. The LEP 102 includes a broad side 106 andeight narrow sides. The eight narrow sides may have substantially equaldimensions. Alternatively, each of the eight narrow sides may have oneor more dimensions that are different respective one or more dimensionsof some or all other narrow sides of the eight narrow sides. In someexample embodiments, the LEP 102 may include grooves on the broad side106. The LEP 102 also includes a second broad side that is opposite thebroad side 106. The second broad side may be covered with a reflectorthat reflects light toward the broad side 106. The second broad side mayalso include grooves.

The lighting device 100 includes four sets of light sources 116, 118,120, 122, which are referred to as four sets of light emitting diodes(LEDs) 116, 118, 120, 122, hereinafter. However, the four sets of lightsources 116, 118, 120, 122 may be light sources other than LEDs.Further, the terms LED and LEDs as used herein may refer to discrete LEDor LEDs, one or more organic light-emitting diodes (OLEDs), an LED chipon board that includes one or more discrete LEDs, an array of discreteLEDs, or light source(s) other than LEDs. Further, each set of lightsources 116, 118, 120, 122 may be a single light source. Continuing withFIG. 1, the four sets of LEDs 116, 118, 120, 122 are each positionedclose to a corresponding narrow side 108, 110, 112, 114 of the LEP. Toillustrate, a first set of LEDs 116 is positioned close to a firstnarrow side 108 of the LEP 102. A second set of LEDs 118 is positionedclose to a second narrow side 110 of the LEP 102. A third set of LEDs120 is positioned close to a third narrow side 112 of the LEP 102. Afourth set of LEDs 122 is positioned close to a fourth narrow side 114of the LEP 102. In some example embodiments, the sets of LEDs 116, 118,120, 122 are disposed on a respective printed circuit board (PCB).

As illustrated in FIG. 1B, the first set of LEDs 116 is positionedopposite to the third set of LEDs 120, and adjacent to the second set ofLEDs 118 and to the fourth set of LEDs 122. Similarly, the second set ofLEDs 118 is positioned opposite to the fourth set of LEDs 122, andadjacent to the first set of LEDs 116 and to the third set of LEDs 120.

In some example embodiments, the first set of LEDs 116 are configured toemit light toward the first narrow side 108 of the LEP 102. The secondset of LEDs 118 are configured to emit light toward the second narrowside 110 of the LEP 102. The third set of LEDs 120 are configured toemit light toward the third narrow side 112 of the LEP 102. The fourthset of LEDs 122 are configured to emit light toward the fourth narrowside 114 of the LEP 102.

The lighting device 100 may illuminate an area around the lightingdevice with a light emitted through the broad side 106 of the LEP 102.The lighting device 100 may emit a light through the broad side 106 ofthe LEP 102 based on one or more lights from the four sets of LEDs 116,118, 120, 122. For example, if all four sets of LEDs 116, 118, 120, 122are powered on, the light emitted by the lighting device 100 through thebroad side 106 of the LEP 102 is based on the light from each of thefour sets of LEDs 116, 118, 120, 122. As another example, if only two ofthe four sets of LEDs are powered on, the light emitted by the lightingdevice 100 through the broad side 106 of the LEP 102 is based on thelights from the two sets of LEDs that are powered. As yet anotherexample, if only one of the four sets of LEDs is powered on, the lightemitted by the lighting device 100 through the broad side 106 of the LEP102 is based only on the light from the particular set of LEDs that arepowered on.

The distribution pattern of the light emitted through the broad side 106of the LEP 102 may depend on the particular set of LEDs that are poweredon or off. For example, the distribution pattern of the light emittedthrough the broad side 106 of the LEP 102 is different when only thefirst set of LEDs 116 and the second set of LEDs 118 are powered on ascompared to when only the first set of LEDs 116 and the third set ofLEDs 120 are powered on. As another example, the distribution pattern ofthe light emitted through the broad side 106 of the LEP 102 is differentwhen only the first set of LEDs 116 and the second set of LEDs 118 arepowered on as compared to when only the second set of LEDs 118 and thefourth set of LEDs 120 are powered on.

For a fixed orientation of the lighting device 100, the distributionpattern of the light emitted through the broad side 106 of the LEP 102is different when only the first set of LEDs 116 and the second set ofLEDs 118 are powered on as compared to when only the second set of LEDs118 and the third set of LEDs 120 are powered on. Similarly, for a fixedorientation of the lighting device 100, the distribution pattern of thelight emitted through the broad side 106 of the LEP 102 is differentwhen only the first set of LEDs 116 and the third set of LEDs 120 arepowered on as compared to when only the second set of LEDs 118 and thefourth set of LEDs 122 are powered on. Thus, the distribution pattern ofthe light emitted through the broad side 106 may be changed by poweringon one or more of the sets of LEDs 116, 118, 120, 122 and powering ofthe remaining sets of LEDs 116, 118, 120, 122. By changing theparticular one or more of the sets of LEDs 116, 118, 120, 122 that arepowered on, the distribution pattern of the light emitted through thebroad side 106 can be changed.

Further, the distribution pattern of the light emitted through the broadside 106 of the LEP 102 may also depend on the intensity of light fromeach of the sets of LEDs 116, 118, 120, 122. In some exampleembodiments, the intensity of light from each powered-on set of LEDs116, 118, 120, 122 may be adjusted to various levels ranging betweenapproximately zero intensity corresponding to no light being emitted(i.e., substantially equivalent to being powered off) and the maximumintensity of light that can be emitted by the particular set of LEDs116, 118, 120, 122. In some example embodiments, intensity level oflight emitted by each one of the sets of LEDs 116, 118, 120, 122 may beset or adjusted to zero by powering off the particular set of LEDs. Theintensity of light from each one of the sets of LEDs 116, 118, 120, 122may also be preset to a desired level prior to being powered on. Thedistribution pattern of the light emitted through the broad side 106 ofthe LEP 102 may be different when one or more sets of LEDs 116, 118,120, 122 are powered to emit light at a full (i.e., one hundred percent)intensity level instead of, for example, at a substantially lessintensity level. For example, the first set of LEDs 116 and the secondset of LEDs 118 may be dimmed to emit light at fifty percent of therespective full intensity level of each set of LEDs 116, 118. Thedistribution pattern of the light emitted through the broad side 106 ofthe LEP 102 is different when the first set of LEDs 116 and the secondset of LEDs 118 are dimmed to emit light at fifty percent of theirrespective full intensity level as compared to when the first set ofLEDs 116 and the second set of LEDs 118 emit light at their respectivefull intensity level.

In some example embodiments, the full intensity level of lights emittedby the four sets of LEDs 116, 118, 120, 122 may be substantially thesame. In alternative embodiments, the full intensity level of lightemitted by some of the sets of LEDs 116, 118, 120, 122 may be differentfrom the full intensity level of light from the other sets of LEDs 116,118, 120, 122. To illustrate, the full intensity level of lights fromthe first set of LEDs 116 and from the third set of LEDs 120 may besubstantially different from the full intensity level of lights from thesecond set of LEDs 118 and from the fourth set of LEDs 122. For example,the full intensity level of light from each of the first set of LEDs 116and the third set of LEDs 120 may be approximately fifty percent of thefull intensity level of light from each of the second set of LEDs 118and the fourth set of LEDs 122. As another example, the full intensitylevel of light from each of the first set of LEDs 116 and the third setof LEDs 120 may be approximately seventy five percent of the fullintensity level of light from each of the second set of LEDs 118 and thefourth set of LEDs 122. By having different intensity levels of lightemitted by the sets of LEDs 116, 118, 120, 122, a desired distributionpattern of the light emitted through the broad side 106 of the LEP 102may be achieved.

In some example embodiments, each of the four sets of LEDs 116, 118,120, 122 may emit light that has a full intensity level that issubstantially different from the full intensity level of light emittedby all other sets of LEDs 116, 118, 120, 122. Thus, the distributionpattern of the light emitted through the broad side 106 may be changedby adjusting intensity of light emitting by one or more of the sets ofLEDs 116, 118, 120, 122.

In some example embodiments, the intensity level of light that each setof LEDs 116, 118, 120, 122 emits may be fixed. For example, the lightingdevice 100 may be designed such that some of the sets of LEDs 116, 118,120, 122 emit light approximately at a first fixed intensity level whilethe remaining sets of LEDs 116, 118, 120, 122 emit light approximatelyat a second fixed intensity level. To illustrate, one or more driversmay provide power to the sets of LEDs 116, 118, 120, 122 such that eachof the sets of LEDs 116, 118, 120, 122 emits light that has an intensitylevel intended to achieve a desired light distribution pattern.

In some example embodiments, the intensity level of light from one ormore of the set of LEDs 116, 118, 120, 122 may be set by a user, such asa consumer or a technician. To illustrate, a user may set the intensitylevel of light from each set of LEDs 116, 118, 120, 122 at time ofinstallation to achieve a desired distribution pattern of the lightemitted through the broad side of the LEP 102. For example, a user maypower on one or more of the sets of LEDs 116, 118, 120, 122 and poweroff the remaining sets of LEDs 116, 118, 120, 122 to achieve a lightdistribution pattern that reduces the level of illumination of aparticular part of the area around the lighting device 100. Further, tochange the light distribution pattern, the user may adjust the intensitylevel of the one or more sets of LEDs that are powered on. As anotherexample, a user may power on all four sets of LEDs 116, 118, 120, 122and configure each set of LEDs to emit light that has a correspondingintensity level that results in a desired distribution pattern of thelight emitted through the broad side of the LEP 102.

In some situations, several of the lighting device 100 may be installedin a particular area. For example, multiple of the lighting device 100may be installed in parking lot. In such scenarios, the lightdistribution in the parking lot may depend on distribution of light froma number of the lighting devices. Thus, overall distribution of light inthe parking lot may be controlled by adjusting the distribution of lightfrom one or more of the lighting device while considering the effect oflight emitted by the other lighting devices on the overall distributionof light.

Further, the distribution of light emitted through the broad side of theLEP 102 of the lighting device 100 may be considered in terms of theNational Electrical Manufacturers Association (NEMA) light distributionstandard and may be classified based on its NEMA type.

In some example embodiments, one or more sets of LEDs 116, 118, 120, 122may be adjustable by a user to emit light that has a desired intensitylevel. In such embodiments, alternatively or in addition to settingintensity levels at time of installation, a user may adjust theintensity level of light from each set of LEDs 116, 118, 120, 122 afterinstallation of the lighting device 100. To illustrate, afterinstallation, a user may adjust the intensity level of light from eachset of LEDs 116, 118, 120, 122 based on one or more factors, such astime of day and occupancy of the area around the lighting device 100.For example, a user may prefer that a portion of the area around thelighting device 100 is highly illuminated at all times while anotherportion of the area is highly illuminated only during a certain periodof time. To achieve light distribution pattern that matches the user'sillumination preference at different time periods, the user may, forexample, power off or dim the light from one or more of the sets of LEDs116, 118, 120, 122 as needed. Similarly, the user may power on orincrease intensity of light from the one or more of the sets of LEDs116, 118, 120, 122 as needed. In some example embodiments, a timer maybe used to control the on-off powering and/or dimming operations.

In some example embodiments, two or more of the sets of LEDs 116, 118,120, 122 may be controlled as a group. For example, the first set ofLEDs 116 and the third set of LEDs 120 may be controlled using a singlecontrol means such as a dimmer and/or a switch. Similarly, the secondset of LEDs 118 and the fourth set of LEDs 122 may be controlled using asingle control means such as a dimmer and/or a switch. Althoughparticular sets of LEDs are described as being controlled as a group, inalternative embodiments, various combinations of the sets of LEDs may becontrolled as a group. Further, as it should be apparent from the abovedescription, each of the four sets of LEDs 116, 118, 120, 122 may beindependently controlled by a corresponding dimmer and/or on-off switch(e.g., a dual in-line (DIP) switch).

In some example embodiments, a single on-off switch may be used to poweron and off all of the sets of LEDs 116, 118, 120, 122 while a dedicateddimmer is used to control a corresponding one of the sets of LEDs 116,118, 120, 122. In general, different combinations of on-off switch anddimmer control arrangements may be implemented for differentapplications.

In some example embodiments, the sensor 105 may be coupled to a switchto control whether one or more of the sets of LEDs 116, 118, 120, 122are turned on or off. For example, the sensor 105 may be a motion sensor105 that senses motion (e.g., cars, pedestrians, etc.) and provides anindication signal to an on-off switch to control whether one or more ofthe sets of LEDs 116, 118, 120, 122 are powered on or off. Alternativelyor in addition, the motion sensor 105 may also be coupled to a dimmer tocontrol the intensity level of light emitted by one or more of the setsof LEDs 116, 118, 120, 122. Although the sensor 105 is shown attached tothe LEP 102 of the lighting device 100, in alternative embodiments, thesensor 105 may be remotely located detached from the lighting device 100or may be attached to another member of the lighting device 100.

In some example embodiments, the sensor 105 may include a light sensor(in addition or alternatively to a motion sensor) that is configured todetect light and provide a corresponding indication signal to an on-offswitch to control whether one or more of the sets of LEDs 116, 118, 120,122 are powered on or off. For example, some of the sets of LEDs may bepowered on in response to the light sensor detecting low light level.Alternatively or in addition to being coupled to an on-off switch, thelight sensor may also be coupled to a dimmer to control the intensitylevel of light emitted by one or more of the sets of LEDs 116, 118, 120,122.

In some example embodiments, the frame 104 may hide the four sets ofLEDs 116, 118, 120, and 122 from view, for example, at viewing anglesbelow the lighting device 100. The frame 104 may also hide from view theoutline of the perimeter of the LEP 104. In some example embodiments,the frame 104 may be made from aluminum, and may have aesthetic feature.The frame 104 may also be part of a heat management structure of thelighting device 100. Although the frame 104 has a substantially circularshape as shown in FIG. 1A, in alternative embodiments, the frame 104 mayhave other shapes without departing from the scope of this description.

Although the LEP 102 is shown in FIG. 1B as having an octagonal shape,in some alternative embodiments, the LEP 102 may have other shapes,including a rectangular shape, a V-shape, and a circular shape, withoutdeparting from the scope of this description. In general, the LEP 102may have a polygon and other non-polygon shape and is not limited to theexample shapes identified in this description and may have fewer or morethan eight narrow sides. Each side of the LEP 102 may also be a straightor a curved side. Further, in some alternative embodiments, the lightingdevice 100 may include fewer or more than four sets of LEDs that emitlight toward correspondingly narrow sides of the LEP 102. For example,the lighting device 100 may include one, two, three, five, or more setsof LEDs that are positioned proximal to a corresponding narrow side ofthe LEP 102 having an octagonal or another shape.

To illustrate, in some example embodiments, the LEP 120 may be acircular-shape LEP. For example, multiple LEDs may be positioned aroundthe outer narrow perimeter of the circular-shape LEP, where each LED iscontrolled (i.e., powered on, power off, and/or adjusted for lightintensity) individually. Alternatively several groups of LEDs may bepositioned around the narrow outer perimeter of the circular-shape LEP,where each group of LEDs is controlled individually. By controllingindividual LEDs or groups of LEDs, distribution of light emitted by thecircular-shape LEP may be changed as desired. In an alternativeembodiment, the circular-shape LEP may have a cut-out (e.g., arectangular cut-out) through the broad sides of the circular-shape LEPand the LEDs may be positioned to emit light into the circular-shape LEPthrough the narrow side in the cut-out.

As another example, the LEP 102 may be a V-shaped LEP, and LEDs or otherlight sources that are controllable individually or in groups may bepositioned, for example, in the valley of the V-shape.

FIG. 2A illustrates the lighting device 100 of FIG. 1A including a setof LEDs that are powered on in accordance with an example embodiment.FIG. 2B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 2A with a single set of LEDs powered on inaccordance with an example embodiment. As illustrated in FIG. 2A, thefirst set of LEDs 116 are powered on while the other sets of LEDs 118,120, 122 shown in FIG. 1B are powered off.

Each curve of the Iso-footcandle plot shown in FIG. 2B (as well as FIGS.3B, 4B, 5B, 6B, and 7A-7D) represents locations on a viewing plane belowthe lighting device 100 that experience substantially the same lightintensity level. The center 202 of the Iso-footcandle plot represents aposition in the viewing plane that is directly below the lighting device100. Thus, points on the plot that are farthest from the center 202represent positions in the viewing plane that are farthest from thelighting device 100. Positions in the viewing plane that are representedby a particular curve experience a light intensity level that isapproximately fifty percent of the light intensity level experienced bypositions represented by an immediately adjacent inner curve.

As can be seen in FIG. 2B, when the first set of LEDs 116 are powered onand the other sets of LEDs 118, 120, 122 are powered off, some locationsin the viewing plane that are at substantially equal distances from thelighting device 100 may experience different levels of light intensity.To illustrate, some positions on the right side of the lighting device100 but that are farther away than closer positions on the left side ofthe lighting device 100 may experience relatively higher levels of lightintensity than the closer positions that are on the left side of thelighting device 100. For example, the farthest right position 204 on theouter most curve 202 experiences the same level of light intensity asthe farthest left position 206 on the curve even though the farthestright position 206 is approximately twice as far from the center 202 oflighting device 100 as the farthest left position.

Accordingly, the lighting device 100 may be set to have only the firstset of LEDs 116 powered on when a desired light distribution patterncorresponds to the pattern illustrated in FIG. 2B.

FIG. 3A illustrates the lighting device of FIG. 1A including two sets ofLEDs that are powered on in accordance with an example embodiment. FIG.3B illustrates an Iso-footcandle plot that corresponds to the lightingdevice of FIG. 3A in accordance with an example embodiment.

As illustrated in FIG. 3A, the first set of LEDs 116 and the third setof LEDs 120 are powered on and the other sets of LEDs 118, 122 arepowered off. As can be seen in FIG. 3B, some locations in the viewingplane that are at substantially equal distances from the lighting device100 may experience different levels of light intensity while otherlocations in the viewing plane that are at equal distance from thelighting device 100 may experience substantially the same level of lightintensity. Further, locations in the viewing plane that are at differentdistances from the lighting device 100 may experience substantially thesame level of light intensity. To illustrate, the farthest rightposition 304 on the outer most curve 312 and the farthest left position306 on the outer most curve 312, which are substantially at equaldistance from the lighting device 100, experience substantially the samelevel of light intensity. Similarly, the farthest back position 308 andthe farthest front position 310 on the outermost curve 312, which are atsubstantially equal distance from the lighting device 100, experiencesubstantially the same level of light intensity. However, the farthestright position 304 and the farthest left position 306 experiencesubstantially the same level of light intensity as the farthest backposition 308 and the farthest front position 310 even though thefarthest right position 304 and the farthest left position 306 aresignificantly farther away from the lighting device 100 than thefarthest back position 308 and the farthest front position 310.

Accordingly, the lighting device 100 may be set to have the first set ofLEDs 116 and the third set of LEDs 120 powered on and the other sets ofLEDs 118, 122 powered off when a desired light distribution pattern ofthe lighting device 100 corresponds to the pattern illustrated in FIG.3B.

FIG. 4A illustrates the lighting device of FIG. 1A including two sets ofLEDs that are powered on in accordance with another example embodiment.FIG. 4B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 4A in accordance with an example embodiment.

As illustrated in FIG. 4A, the first set of LEDs 116 and the second setof LEDs 118 are powered on and the other sets of LEDs 120, 122 arepowered off. As can be seen in FIG. 4B, some locations in the viewingplane that are at substantially equal distances from the lighting device100 may experience different levels of light intensity while otherlocations in the viewing plane that are equal distance from the lightingdevice 100 may experience substantially the same level of lightintensity. Further, locations in the viewing plane that are at differentdistances from the lighting device 100 may experience substantially thesame level of light intensity. To illustrate, the farthest rightposition 404 on the outer most curve 412 and the farthest left position406 on the outer most curve 412, which are at substantially differentdistances from the lighting device 100, experience substantially thesame level of light intensity. Similarly, the farthest back position 408and the farthest front position 410 on the outermost curve 412, whichare substantially at substantially different distances from the lightingdevice 100, experience substantially the same level of light intensity.However, the farthest right position 404 and the farthest front position410, which are at substantially equal distance from the lighting device100, experience substantially the same level of light intensity.

Accordingly, the lighting device 100 may be set to have the first set ofLEDs 116 and the second set of LEDs 118 powered on and the other sets ofLEDs 120, 122 powered off when a desired light distribution pattern ofthe lighting device 100 corresponds to the pattern illustrated in FIG.4B. Even though only two of the sets of LEDs are powered on in bothFIGS. 3A and 4A, the light distribution patterns that correspond toFIGS. 3A and 4A are significantly different from each other as can beclearly seen by comparing the corresponding Iso-footcandle plots shownin FIGS. 3B and 4B.

FIG. 5A illustrates the lighting device of FIG. 1A including three setsof LEDs that are powered on in accordance with an example embodiment.FIG. 5B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 5A in accordance with an example embodiment.

As illustrated in FIG. 5A, the first set of LEDs 116, the second set ofLEDs 118, and the fourth set of LEDs 120 are powered on and the thirdset of LEDs 120 are powered off. As can be seen in FIG. 5B, somelocations in the viewing plane that are at different distances from thelighting device 100 may experience substantially the same level of lightintensity. To illustrate, the farthest right position 504, the farthestback position 508 on the same curve, and the farthest front position510, which are all on the same curve 512 and significantly farther fromthe lighting device 100 than the farthest left position 506, experiencesubstantially the same level of light intensity as the farthest leftposition 506. Further, the farthest right position 504, the farthestback position 508, and the farthest front position 510, which all are atapproximately equal distances from the lighting device 100, experiencesubstantially the same level of light intensity. An overall comparisonof the Iso-footcandle plots of FIGS. 3B, 4B, and 5B shows, thedistribution pattern of the light represented by the Iso-footcandle plotof FIG. 5B is different from the light distribution patterns representedby the Iso-footcandle plots of FIGS. 3B and 4B.

Accordingly, as illustrated in FIG. 5A, the lighting device 100 may beset to have the first set of LEDs 116, the second set of LEDs 118, andthe fourth set of LEDs 120 powered on and the third set of LEDs 120powered off when a desired light distribution pattern of the lightingdevice 100 corresponds to the pattern illustrated in FIG. 5B.

FIG. 6A illustrates the lighting device of FIG. 1A including four setsof LEDs that are powered on in accordance with an example embodiment.FIG. 6B illustrates an Iso-footcandle plot that corresponds to thelighting device of FIG. 6A in accordance with an example embodiment. Asillustrated in FIG. 6A, all four sets of LEDs 116, 118, 120, 122 arepowered on. As can be seen in FIG. 6B, unlike the light distributionpattern illustrated in FIGS. 3B, 4B, and 5B, all locations in theviewing plane that are substantially equally distanced from the lightingdevice 100 experience substantially the same level of light intensity.In addition, the overall distribution pattern of the light representedby the Iso-footcandle plot of FIG. 6B is different from the lightdistribution patterns represented by the Iso-footcandle plots of FIGS.3B, 4B, and 5B.

FIGS. 7A-7D are Iso-footcandle plots illustrating effects of differentintensity levels of lights from different light sources on the lightdistribution pattern of a lighting device in accordance with an exampleembodiment. For illustrative purposes, the inner curve in each of theIso-footcandle plots of FIGS. 7A-7D may be a 0.2 foot-candle (fc) curve,and the outer curve may be a 0.1 fc curve.

In an example embodiment, the Iso-footcandle plot on FIG. 7A correspondsto the lighting device 100 illustrated in FIG. 6A, where all four setsof LEDs 116, 118, 120, 122 are powered on. For example, theIso-footcandle plot on FIG. 7A may correspond to all four sets of LEDs116, 118, 120, 122 emitting light that are each substantially at a fullintensity level. In some example embodiments, the Iso-footcandle plot onFIG. 7B may correspond to the lighting device 100 illustrated in FIG.6A, where the first set of LEDs 116 and the third set of LEDs 120 emitlight at substantially full intensity level, and where the second set ofLEDs 118 and the fourth set of LEDs 122 emit light at substantiallyfifty percent of the full intensity level. In some example embodiments,the Iso-footcandle plot on FIG. 7C may correspond to the lighting device100 illustrated in FIG. 6A, where the first set of LEDs 116 and thethird set of LEDs 120 emit light at substantially full intensity level,and where the second set of LEDs 118 and the fourth set of LEDs 122 emitlight at substantially twenty five percent of the full intensity level.In some example embodiments, the Iso-footcandle plot on FIG. 7D maycorrespond to the lighting device 100 illustrated in FIG. 3A, where thefirst set of LEDs 116 and the third set of LEDs 120 emit light at asubstantially full intensity level, and where the second set of LEDs 118and the fourth set of LEDs 122 are powered off (alternatively, dimmed tosubstantially zero percent of the full intensity level).

As comparison of the Iso-footcandle plots of FIGS. 7A-7D illustrates,changes in the intensity level of light emitted by two of the sets ofLEDs 116, 118, 120, 122 affects the light distribution pattern of thelighting device 100. Accordingly, the lighting device 100 may beconfigured to emit light that has a particular light distributionpattern by setting or adjusting one or more of the sets of LEDs 116,118, 120, 122 to emit a light that has a particular level of intensity.

Although FIGS. 7A-7D are described with respect to four sets of LEDswhere intensity level of light from two of the four sets of LEDs are setor adjusted, in alternative embodiments, only one or more than two ofthe four sets may be set and/or adjusted to emit light so that each haveparticular levels of intensity to produce a particular distributionpattern of the light from the lighting device 100. Further, as describedabove, in some alternative embodiments, the lighting device 100 may havefewer or more than four sets of LEDs. In addition, although particularlevels of light intensity are described, the intensity of light fromeach set of LEDs may be adjusted to have a level ranging between a fullintensity level and substantially being powered off. Further, asdescribed above, in some example embodiments, the level of lightintensity of light from each set of LEDs may be independentlycontrolled.

FIG. 8 is a flowchart illustrating a method of controlling lightdistribution pattern of an edge-lit lighting device in accordance withan example embodiment. The method 800 includes installing an edge-litlighting device, at step 802. For example, a technician may install theedge-lit lighting device, such as the edge-lit lighting device 100 ofFIG. 1A. To illustrate, the edge-lit lighting device may include a lightemitting panel (LEP), a first plurality of light emitting diodes (LEDs)positioned proximal to a first narrow side of the LEP and configured toemit a first light toward the first narrow side, and a second pluralityof LEDs positioned proximal to a second narrow side of the LEP andconfigured to emit a second light toward the second narrow side. Forexample, the first plurality of LEDs may correspond to the first set ofLEDs 116 of FIG. 1B. Similarly, the second plurality of LEDs maycorrespond to, for example, the second set of LEDs 118 or the third setof LEDs 120 of FIG. 1B.

The method 800 further includes setting an intensity level of the firstlight, at step 804. For example, the first plurality of LEDs may be setto emit light at a full intensity level. The method 800 also includessetting an intensity level of the second light, at step 806. Forexample, the second plurality of LEDs may be set to emit light at a fullintensity level as well. Alternatively, the second plurality of LEDs maybe set to emit light at approximately fifty percent of the fullintensity level.

In some example embodiments, the method 800 also includes adjusting theintensity level of the first light, at step 808. For example, adjustingthe intensity level of the first light may include dimming the firstlight. Alternatively or in addition, the method 800 may also includeadjusting the intensity level of the second light.

FIG. 9 illustrates the lighting device 100 of FIG. 1A according toanother example embodiment. Referring to FIGS. 1A-9, in some exampleembodiments, the lighting device (e.g., a lighting fixture) 100 includesthe LEP 102, the frame 104, and the sensor 105. As described above, thesensor 105 may include a light sensor and a motion sensor. The lightingdevice 100 may also include a back cover 906 that may be attached to theframe 104 at a back side of the lighting device 102.

In some example embodiments, the lighting device 100 may include asensor shield 902 that is positioned to shield the sensor 105 from atleast a portion of the light emitted by the lighting device 100 throughthe broad side 106 of the LEP 102 (i.e. illumination light). Forexample, a portion of the sensor 105 may be positioned in a cavity 904of the sensor shield 902. To illustrate, a portion of the sensor shield902 may be positioned around a portion of the sensor 105 to prevent someof the light emitted from the LEP 102 from directly reaching the sensor105. The sensor shield 902 may be positioned such that the sensor 105can detect ambient light while interference by the light emitted fromthe LEP 102 is reduced by the sensor shield 902.

In some example embodiments, the sensor shield 904 may also bepositioned around the sensor 105 such that the desired motion sensingrange of the sensor 105 is not impaired or excessively impaired by thesensor shield 904. For example, one or both of the distance range andthe angular range of the sensor 105 for sensing motion may be withindesired ranges or may not be excessively less than desired ranges.

By reducing the amount of light from the lighting device 100 thatdirectly reaches the sensor 105, the sensor shield 902 can enable thesensor 105 to more effectively sense ambient light. Reducing theinterference of the light from the lighting device 100 in the detectionof ambient light enables the lighting device 100 to more effectivelycontrol the light provided by the lighting device 100. By reducing theamount of light from the lighting device 100 that directly reaches thesensor 105 with no or limited interference in the motion sensing andambient light sensing, the sensor shield 902 can enable the lightingdevice 100 to more effectively control its operations.

In some alternative embodiments, the sensor shield 902 and/or the sensor105 each may have a different shape than shown without departing fromthe scope of this disclosure. In some alternative embodiments, the LEP102 and/or the frame 104 may each have a different shape than shownwithout departing from the scope of this disclosure. In some alternativeembodiments, the sensor 105 may not include motion sensor withoutdeparting from the scope of this disclosure.

FIG. 10 illustrates the sensor shield 902 attached to the sensor 105 ofthe lighting device 100 of FIG. 9 according to an example embodiment.Referring to FIGS. 1A-10, in some example embodiments, the sensor 105may include a sensor body 1002, a sensor lens 1004, and shaft section1006 extending between the sensor body 1002 and the sensor lens 1004.The sensor 105 may detect motion and light through the lens 1004. Theshaft section 1006 may extend through the attachment nut 1008 such thatthe attachment nut 1008 is rotated around the shaft section 1006 to movethe attachment nut 1008 upward toward the LEP 102 to firmly attach thesensor 105 to the LEP 102.

In some example embodiments, the sensor shield 902 may include a skirtportion 1010 and a back portion 1012. The shaft section 1006 may extendthrough an opening in the back portion 1012. The sensor 105 may beassembled by attaching the shaft section 1006 to the sensor lens 1004and/or to the sensor body 1002 after the shaft section 1006 is extendedthrough the opening of the back portion 1012 of the sensor shield 902.The back portion 1012 of the sensor shield 902 may rest on or mayotherwise be positioned at the back side of the lens 1004 of the sensor105. The skirt section 1010 of the sensor shield 902 may extend downfrom the back portion 1012 of the sensor shield 902 such that the skirtportion 1010 extends circumferentially around the lens 1004 of thesensor 105. For example, the skirt portion 1010 may extend around thesensor lens 1004 such that the skirt portion 1010 prevents the lightfrom the LEP 102 from directly reaching the sensor lens 1004.

In some example embodiments, the skirt portion 1010 may have an outerperimeter edge 1014, and the skirt section 1010 may extend down suchthat a bottom end portion of the sensor lens 1004 is slightly below theouter perimeter edge 1014 of the skirt portion 1010. To illustrate, thebottom end portion of the sensor lens 1004 may be outside the cavity 904of the sensor shield 902. For example, the bottom end portion of thesensor lens 1004 may be a portion of the sensor lens 1004 that is usedin sensing ambient light. Although the bottom end portion of the sensorlens 1004 is below the outer perimeter edge 1014 (i.e., outside thecavity 904), the skirt portion 1010 may still prevent the light from theLEP 102 from directly reaching the sensor lens 1004. Because the bottomend portion of the sensor lens 1004 is below the outer perimeter edge1014, the sensor shield 902 may allow the sensor 105 to provide adesired level of ambient light sensing while preventing direct lightfrom the LEP 102 from reaching the sensor 105.

In some example embodiments, a portion of the sensor lens 1004 that isused in motion sensing by the sensor 105 may be fully inside the cavity904 of the sensor shield 902. For example, the skirt portion 1010 mayextend circumferentially around the motion sensing portion of the sensorlens 1004. The sensor 105 may have a motion sensing viewing angle thatfollows the motion sensing viewing line 1016 around the outer perimeteredge 1014 of the skirt portion 1010. To illustrate, the motion sensingviewing line 1016 may depend on the height of the skirt portion 1010between the outer perimeter edge 1014 and the back portion 1012 of theskirt portion 1010. That is, the motion sensing viewing line 1016 maydepend on how much the skirt portion 1010 extends below the verticallevel 1018 of the motion sensing portion of the sensor lens 1004.Although the motion sensing range of the sensor 105 may be reduced bythe sensor shield 902 in contrast to embodiments of the lighting device100 that do not include the sensor shield 902, the sensor shield 902 maystill allow the sensor 105 to have a desired motion sensing range.

In some alternative embodiments, the skirt portion 1010 may extend downto a level that is higher or level than shown in FIG. 10 withoutdeparting from the scope of this disclosure. In some alternativeembodiments, the different components of the sensor 105 may havedifferent shapes than shown without departing from the scope of thisdisclosure. In some example embodiments, one or more components of thesensor 105 may be integrated into a single component without departingfrom the scope of this disclosure.

FIG. 11 illustrates the sensor of the lighting device of FIG. 9according to an example embodiment. Referring to FIGS. 1A-11, in someexample embodiments, the sensor lens 1004 may include a light sensingportion 1102 and a motion sensing section 1104. As described above withrespect to FIG. 10, the light sensing portion 1102 may extend slightlybelow the skirt portion 1010 of the sensor shield 902, while the motionsensing section 1104 may be above the outer perimeter edge 1014 of theskirt portion 1010. In some alternative embodiments, both the lightsensing portion 1102 and the motion sensing section 1104 may be below orabove the outer perimeter edge 1014 of the skirt portion 1010.

In some alternative embodiments, the motion sensing portion 1104 mayextend slightly below the skirt portion 1010 of the sensor shield 902,while the light sensing section 1102 may be above the outer perimeteredge 1014 of the skirt portion 1010. In some alternative embodiments,the lighting device 100 may include a different type of sensor withoutdeparting from the scope of this disclosure.

FIGS. 12 and 13 illustrate different views of the sensor shield of thelighting device of FIG. 9 according to an example embodiment. Referringto FIGS. 1A-13, in some example embodiments, the sensor shield 902 mayinclude the skirt portion 1010 and the back portion 1012, where the backportion 1012 has an opening 1202 formed therethrough. The sensor shield902 may be attached to the sensor 105 by extending the shaft section1006 of the sensor 105 through the opening 1202. For example, the backcover 1012 may be position on the lens 1004 after the shaft section 1006is extended through the opening 1202 such that the lens 1004 ispositioned at least partially in the cavity 904 of the sensor shield902.

In some example embodiments, the cylindrical shape of the skirt portion1010 may provide a 360 degree blockage of direct light from the LEP 102from reaching the sensor lens 1004. Because light is detected by thesensor 105 through the sensor 1004, the blockage of direct light fromthe LEP 102 may allow sensor 105 to more effectively detect ambientlight near the lighting device 100. The sensor shield 902 may be madefrom an optically opaque material to effectively block light. Forexample, the sensor shield may be made from a plastic material or ametallic material (e.g., aluminum) using methods, such as bending,cutting, etc., as can be readily contemplated by those of ordinary skillin the art with the benefit of this disclosure.

FIG. 14 illustrates the inside of the lighting device of FIG. 9according to an example embodiment. Referring to FIGS. 1A-14, in someexample embodiments, the lighting device 100 includes electrical wires1402 that are used to provide power to the lighting device 100. Forexample, at least some of the electrical wires 1402 may be routed to adriver 1404 that provides power to the light sources 1408 and otherlight sources of the lighting device 100. The driver 1404 may bepositioned in a cavity of the back cover 906 For example, the lightsources 1408 may correspond to the light sources 116, 118, 120, or 122.As shown in FIG. 14, the light sources 1408 may be positioned against agasket 1408 to emit light into the LEP 102 through a narrow side of theLEP 102. As the light exits the LEP 102 through the broad side 106 ofthe LEP 102, the sensor shield 902 blocks the light from directlyreaching the sensor 105. Because the sensor shield 902 is open at itsbottom end, the sensor 105 has large motion and light sensing rangeswith respect to distance and angle with reduced interference from thelight emitted through the broad side 106 of the LEP 102.

Although particular embodiments have been described herein in detail,the descriptions are by way of example. The features of the embodimentsdescribed herein are representative and, in alternative embodiments,certain features, elements, and/or steps may be added or omitted.Additionally, modifications to aspects of the embodiments describedherein may be made by those skilled in the art without departing fromthe scope of the following claims, the scope of which are to be accordedthe broadest interpretation so as to encompass modifications andequivalent structures.

What is claimed is:
 1. An edge-lit lighting fixture, comprising: a lightemitting panel (LEP); a light emitting diode (LED) light sourcepositioned proximal to a perimeter edge of the LEP and configured toemit a light into the LEP through the perimeter edge, wherein at least aportion of the light is emitted through a broad surface of the LEP as anillumination light to illuminate an area; a sensor positioned at thebroad surface of the LEP to detect ambient light in the area, whereinthe LED light source is powered on based on the sensor; and a sensorshield positioned around a portion of the sensor to block theillumination light from directly reaching the sensor.
 2. The edge-litlighting fixture of claim 1, wherein the sensor shield comprises a skirtportion that extends around a lens of the sensor to block theillumination light from directly reaching the lens of the sensor.
 3. Theedge-lit lighting fixture of claim 2, wherein a bottom end portion ofthe lens of the sensor is outside a cavity of the sensor shield.
 4. Theedge-lit lighting fixture of claim 3, wherein the bottom end portion ofthe lens of the sensor is used in light sensing by the sensor.
 5. Theedge-lit lighting fixture of claim 3, wherein a portion of the lens ofthe sensor used in motion sensing by the sensor is inside the cavity ofthe sensor shield.
 6. The edge-lit lighting fixture of claim 1, whereina shaft section of the sensor extends through an opening in a backportion of the sensor shield to retain the sensor shield attached to thesensor.
 7. The edge-lit lighting fixture of claim 1, wherein the LEP hasa circular shape.
 8. The edge-lit lighting fixture of claim 2, whereinthe sensor is positioned at a center of the broad surface of the LEP. 9.The edge-lit lighting fixture of claim 1, further comprising a secondLED light source positioned proximal to the perimeter edge of the LEPand configured to emit a second light into the LEP through the perimeteredge, wherein the first LED light source and the second LED light sourceare positioned opposite to each other with respect to the LEP.
 10. Theedge-lit lighting fixture of claim 9, wherein the first LED light sourceand the second LED light source are positioned approximately 90 degreesfrom each other with respect to a center of the LEP.
 11. An edge-litlighting fixture, comprising: a light emitting panel (LEP); a lightemitting diode (LED) light source positioned proximal to a perimeteredge of the LEP and configured to emit a light into the LEP through theperimeter edge, wherein at least a portion of the light is emittedthrough a broad surface of the LEP as an illumination light toilluminate an area; a sensor positioned at the broad surface of the LEPto detect ambient light in the area, wherein the LED light source ispowered on based on the sensor; a sensor shield positioned around aportion of the sensor to block the illumination light from directlyreaching the sensor; and a frame positioned adjacent the perimeter edgeof the LEP.
 12. The edge-lit lighting fixture of claim 11, wherein thesensor is positioned at a center of the broad surface of the LEP. 13.The edge-lit lighting fixture of claim 12, wherein the LEP has acircular shape.
 14. The edge-lit lighting fixture of claim 12, whereinthe sensor shield comprises a skirt portion that extends around a lensof the sensor to block the illumination light from directly reaching thelens of the sensor.
 15. The edge-lit lighting fixture of claim 14,wherein a bottom end portion of the lens of the sensor is outside acavity of the sensor shield.
 16. The edge-lit lighting fixture of claim15, wherein the bottom end portion of the lens of the sensor is used inlight sensing by the sensor.
 17. The edge-lit lighting fixture of claim15, wherein a portion of the lens of the sensor used in motion sensingby the sensor is inside the cavity of the sensor shield.
 18. Theedge-lit lighting fixture of claim 11, further comprising a second LEDlight source positioned proximal to the perimeter edge of the LEP andconfigured to emit a second light into the LEP through the perimeteredge, wherein the first LED light source and the second LED light sourceare positioned opposite to each other with respect to the LEP.
 19. Theedge-lit lighting fixture of claim 11, wherein the LED light source ishidden from view from below the edge-lit lighting fixture by the frame.20. The edge-lit lighting fixture of claim 18, wherein the frame has acircular outer perimeter and a circular inner perimeter, wherein thefirst LED light source and the second LED light source are covered fromview from below the edge-lit lighting fixture by the frame.